LED display is not a normal electrical appliance formed in the factory at once, but a product produced on site according to customer requirements and installation environment. The failure rate is much higher than other electrical appliances. Therefore, the rigor of on-site production personnel and the after-sales of manufacturers high expectation.
In recent years, the application of small-pitch led display screens has become more and more popular. With the unique advantages of display effects, its application venues range from ordinary conference rooms, monitoring rooms, exhibition display applications, to national-level conference centers, monitoring centers, and CCTV. , And large-scale events. Such as G20 meeting, Zhu Rihe parade, Tianjin National Games, small-pitch led display is everywhere.
However, as a new technology and high-precision equipment, in addition to the excellent display effect, user needs are also accompanied by stability considerations, because once the black screen appears in the main venue, it will cause significant international influence, even political influence, such as Tianjin National Games 5 rings will become 4 rings.
Analysis of application fields of small-pitch display
As a new generation of indoor professional display panels, small-pitch LEDs have the most direct impact on traditional DLP. Changing the angle means that small-pitch LEDs are actually a technical replacement for DLP in product applications. But this substitution is not simply one-to-one. There is still a great difference in application between the small-pitch LED display and DLP, so the technical selection of the screen is particularly important in different projects.
Therefore, when the small-pitch LED is used as the main screen of the venue, its stability assessment is the top priority, and the first one is that it cannot be black.
An Analysis of the Cause of Black Screen
It is precisely because of this demand that we thoroughly analyze the reasons for black screens to fundamentally eliminate the hidden dangers of black screens and truly achieve never black screens. The display screen is an electronic device, the internal control card chip is an FPGA, and there is no operating system. Therefore, the cause of the black screen can be classified into 2 parts, one is a device failure and the other is a cable failure.
1: equipment failure
The device failure mainly occurs in two devices, the receiving card and the switching power supply.
A: receiving card
There are many devices on the receiving card. An ordinary receiving card integrates two Gigabit network communication interfaces, 120P lamp board drive interfaces, SDRAM, FLASH, etc. The solder joints exceed 10,000 points. Because the LED is an inductive load, it causes its The working environment is more complicated. Some manufacturers sacrifice internal heat dissipation space in pursuit of ultra-thin, use mini small cards, etc., their electronic devices have many contacts, the electromagnetic environment is complex, and the internal high thermal environment leads to reduced working stability. An occasional capacitor failure may cause the screen The display is abnormal.
B: switching power supply failure
The LED display is an inductive load, and the output load changes with the screen, which has a large impact on the internal devices. In addition, there are many internal capacitors in the switching power supply. Some manufacturers use switching power supplies with automatic fan cooling to reduce the cost of use. Both capacitors and fans have a short service life, so it becomes the most frequent cause of switching power supply failures, and black screen failures caused by power failures rank first in the entire device.
2: cable fault
Cable faults are mainly divided into external connection cables, such as cables that provide power and signals to the screen, and internal cable faults, such as internal DC power cables and internal gray cables.
A: External cable
Among the external cables, the signal cable has the highest failure rate and the greatest impact. The conventional signal cable used for the display screen is cat5e cable. Due to factors such as material construction, it is difficult to ensure the stability of signal communication. Especially the 2-terminal crystal head is docked, and the vibration resistance is relatively poor.
B: Internal cable
The internal cables are mainly gray cables, as shown below. The gray cable is mostly made by cold pressing. After many times of plugging and unplugging, the contacts are very easy to make poor contact, and even the gray cable is broken. Therefore, the internal cable fault is the highest among all cable connection faults.
Strategies for never black screen
The above analysis of several reasons for the black screen, we will take the right medicine, shield the above problems from the design side, and fulfill the promise to customers and users-never black screen.
One of the never black screen weapon: no receiving card
Compared with the traditional receiving card design, our company adopts a non-receiving card solution to integrate the product highly.
A special chip with higher integration is designed on the adapter board. The chip integrates Gigabit network communication, FPGA, SRAM, FLASH, MCU, etc. in the conventional receiving card, from the original 7 ICs to 1 IC, highly integrated, reducing 80% solder joint connection, from the front end Reduce the failure rate of electronic devices, thereby improving system stability.
Never black screen weapon two: no cable, hard connector
Compared with the cable connection just now, there is no connecting cable inside, and all transmission is carried out through the PCB and the connector. From the design end, the fatigue of multiple plugging and unplugging of the cable and poor contact caused by conventional cold pressing are avoided. Hidden dangers.
Never black screen weapon three: dual power supply
As mentioned above, among the device failures, the switching power supply failure is the first place, so for high-end application sites, dual power backup is generally used. At the same time, the switching power supply designed by our company has an automatic current sharing function, that is, two power supplies output at the same time, which can reduce the work load of the power supply, extend the service life of the power supply, and avoid the impact of the power grid caused by the cold switching of the power supply. The display jitter or the third harmonic causes the device to restart, and at the same time, the power status can be monitored in real time on the software side, and it can also be quickly replaced during maintenance to eliminate the fault.
The fourth never-black screen weapon: loop design
According to the level and cost budget of on-site signal stability requirements, our products can complete 4 levels of backup. The two most important levels of backup are dual interface, dual loop, and dual interface four loop. The dual-interface dual-loop is generally used for TV stations, while the dual-interface four-loop is used for live broadcasting, national live meetings, etc.
Dual interface dual loop for never black screen loop design
As shown in the figure above, the dual signal constitutes two independent signal loops, which can ensure that when one set of loops fails, the other set of loops can be switched over immediately, the switching time is less than 0.1 ms. For places where some TV stations require hot-standby power interfaces, power connectors can be added to achieve dual-channel power supply and dual-channel signal on-screen. At the splicer end, 2 independent copy signals are output to 2 sending boxes through the backup board.
Dual-interface four-loop with never black screen loop design
The backup level is the highest level, that is, the four input ports of the signal, as long as one is normal, it can work normally. The main screen of the Guangzhou Asian Games venue uses this backup mode. Of course, this backup method will increase the cost of the front-end equipment, which is usually more than 4 times that of the conventional configuration.
The end of the never black screen
There is no best, only better, the road of science and technology is endless. The people of Altai adhere to the characteristics of professionalism, research and perseverance, and continue to work on LED display products; through in-depth contact and communication with customers, they continue to develop small-pitch products that meet market needs. And through the advantages of technology precipitation, gradually promote the LED display to a wider application market, use technical strength to eliminate customers' worries, and create maximum value for customers.